Elasticsearch系统学习（三）-document基本操作

一、document数据格式

（1）应用系统的数据结构都是面向对象的，复杂的
（2）对象数据存储到数据库中，只能拆解开来，变为扁平的多张表，每次查询的时候还得还原回对象格式，相当麻烦
（3）ES是面向文档的，文档中存储的数据结构，与面向对象的数据结构是一样的，基于这种文档数据结构，es可以提供复杂的索引，全文检索，分析聚合等功能
（4）es的document用json数据格式来表达

{
    "email":      "zhangsan@sina.com",
    "first_name": "san",
    "last_name": "zhang",
    "info": {
        "bio":         "curious and modest",
        "age":         30,
        "interests": [ "bike", "climb" ]
    },
    "join_date": "2017/01/01"
}

二、简单集群管理

2.1、快速检查集群的健康状况

es提供了一套api，叫做cat api，可以查看es中各种各样的数据，使用GET /_cat/health?v查看集群状态，?v添加表头

GET /_cat/health?v

epoch      timestamp cluster       status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1567342207 20:50:07  elasticsearch yellow          1         1      1   1    0    0        1             0                  -                 50.0%

集群的健康状态：

green：每个索引的primary shard和replica shard都是active状态的
yellow：每个索引的primary shard都是active状态的，但是部分replica shard不是active状态，处于不可用的状态
red：不是所有索引的primary shard都是active状态的，部分索引有数据丢失了

为什么现在会处于一个yellow状态？

我们现在就一个笔记本电脑，就启动了一个es进程，相当于就只有一个node。现在es中有一个index，就是kibana自己内置建立的index。由于默认的配置是给每个index分配5个primary shard和5个replica shard，而且primary shard和replica shard不能在同一台机器上（为了容错）。现在kibana自己建立的index是1个primary shard和1个replica shard。当前就一个node，所以只有1个primary shard被分配了和启动了，但是一个replica shard没有第二台机器去启动。

实验测试：

此时只要启动第二个es进程，就会在es集群中有2个node，然后那1个replica shard就会自动分配过去，然后cluster status就会变成green状态。

epoch      timestamp cluster       status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1567342754 20:59:14  elasticsearch green           2         2      2   1    0    0        0             0                  -                100.0%

2.2、快速查看集群中有哪些索引

GET /_cat/indices?v

GET _cat/indices?v

health status index   uuid                   pri rep docs.count docs.deleted store.size pri.store.size
green  open   .kibana mtCLy37mTr-eW0g1ATAEFw   1   1          1            0      6.3kb          3.1kb

2.3、简单索引操作

1）创建索引：PUT /test_index?pretty

PUT /test_index?pretty

{
  "acknowledged": true,
  "shards_acknowledged": true
}

GET /_cat/indices?v

health status index      uuid                   pri rep docs.count docs.deleted store.size pri.store.size
green  open   .kibana    mtCLy37mTr-eW0g1ATAEFw   1   1          1            0      6.3kb          3.1kb
green  open   test_index cpTW7zzOQkKm9Mi7Omu2Sw   5   1          0            0      1.2kb           650b  #新创建的索引

2）删除索引：DELETE /test_index?pretty

DELETE /test_index?pretty

{
  "acknowledged": true
}

GET /_cat/indices?v

health status index   uuid                   pri rep docs.count docs.deleted store.size pri.store.size
green  open   .kibana mtCLy37mTr-eW0g1ATAEFw   1   1          1            0      6.3kb          3.1kb

三、文档的CRUD操作

3.1、新增商品：新增文档，建立索引

格式：

PUT /index/type/id
{
  "json数据"
}

添加测试用文档：

PUT /ecommerce/product/1
{
    "name" : "gaolujie yagao",
    "desc" :  "gaoxiao meibai",
    "price" :  30,
    "producer" :      "gaolujie producer",
    "tags": [ "meibai", "fangzhu" ]
}

#返回
{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 1,
  "result": "created",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "created": true
}

#在添加两条
PUT /ecommerce/product/2
{
    "name" : "jiajieshi yagao",
    "desc" :  "youxiao fangzhu",
    "price" :  25,
    "producer" :      "jiajieshi producer",
    "tags": [ "fangzhu" ]
}

PUT /ecommerce/product/3
{
    "name" : "zhonghua yagao",
    "desc" :  "caoben zhiwu",
    "price" :  40,
    "producer" :      "zhonghua producer",
    "tags": [ "qingxin" ]
}

es会自动建立index和type，不需要提前创建，而且es默认会对document每个field都建立倒排索引，让其可以被搜索

3.2、查询商品，检索文档

格式：GET /index/type/id

GET /ecommerce/product/1

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 1,
  "found": true,
  "_source": {
    "name": "gaolujie yagao",
    "desc": "gaoxiao meibai",
    "price": 30,
    "producer": "gaolujie producer",
    "tags": [
      "meibai",
      "fangzhu"
    ]
  }
}

3.3、修改商品：替换文档

替换方式有一个不好，必须带上所有的field，才能去进行信息的修改

GET /ecommerce/product/1

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 1,
  "found": true,
  "_source": {
    "name": "gaolujie yagao",
    "desc": "gaoxiao meibai",
    "price": 30,
    "producer": "gaolujie producer",
    "tags": [
      "meibai",
      "fangzhu"
    ]
  }
}

#替换
PUT /ecommerce/product/1
{
    "name" : "jiaqiangban gaolujie yagao",   #名称改变
    "desc" :  "gaoxiao meibai",
    "price" :  30,
    "producer" :      "gaolujie producer",
    "tags": [ "meibai", "fangzhu" ]
}

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 2,
  "result": "updated",
  "_shards": {
    "total": 2,
    "successful": 2,
    "failed": 0
  },
  "created": false
}

#再次查看
{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 2,
  "found": true,
  "_source": {
    "name": "jiaqiangban gaolujie yagao",  #更改了
    "desc": "gaoxiao meibai",
    "price": 30,
    "producer": "gaolujie producer",
    "tags": [
      "meibai",
      "fangzhu"
    ]
  }
}

#缺点：当使用如下替换时，只会剩下name
PUT /ecommerce/product/1
{
    "name" : "jiaqiangban gaolujie yagao"
}

3.4、修改商品：更新文档

格式：POST /index/type/id/_update

GET /ecommerce/product/1

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 3,
  "found": true,
  "_source": {
    "name": "gaolujie yagao",
    "desc": "gaoxiao meibai",
    "price": 30,
    "producer": "gaolujie producer",
    "tags": [
      "meibai",
      "fangzhu"
    ]
  }
}

POST /ecommerce/product/1/_update
{
  "doc":{
    "name": "jiaqiangban gaolujie yagao"
  }
}

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 4,
  "result": "updated",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}

get /ecommerce/product/1

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 4,
  "found": true,
  "_source": {
    "name": "jiaqiangban gaolujie yagao",
    "desc": "gaoxiao meibai",
    "price": 30,
    "producer": "gaolujie producer",
    "tags": [
      "meibai",
      "fangzhu"
    ]
  }
}

3.5、删除商品：删除文档

格式：DELETE /index/type/id

delete /ecommerce/product/1

{
  "found": true,
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 5,
  "result": "deleted",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}

GET /ecommerce/product/1

{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "found": false
}